The present invention relates generally to military decoys, and more particularly to an inexpensive inflatable thermal target decoy.
Military decoys are primarily used for either of two purposes. One is simulating full size military targets to mislead an enemy. The other, and more common, purpose is to simulate military targets for target practice.
Target decoys should be inexpensive, convenient and realistic. A presently popular construction method for making target decoys that simulate a complex target in three dimensions, and which can be quickly deployed from a compact package and later quickly dismantled, is to use balloon-like inflatable membranes. An important requirement for such decoys is that they present a realistic thermal image to thermal imaging surveillance. To provide thermal contrast detailing, and thus make a deceptively realistic thermal signature for the inflatable decoy targets, the prior art has generally placed electric resistance heater panels on the decoys to simulate engine covers or other outside surface components that normally would be proportionally warmer than the rest of the decoy surface. These thermal panels generally double the cost of the inflatable decoy. Passive solar heating has also been used for daytime applications.
The prior art includes a variety of other methods for simulating thermal signatures on a decoy. While these other methods apparently have not been used in combination with an inflatable decoy, their teachings could be applied to inflatable target decoys. For example, U.S. Pat. No. 4,279,599 to Marshall et al teaches the use of an etched flat metal plate where the etched surface is more emissive than its surrounding unetched area and, from solar heating of the plate, presents a deceptively warmer surface area. Where sufficient sunlight is not available to heat the plate, Marshall et al teaches attaching an electric contact heater to the back of the plate.
Another example of a prior art teaching that could be adapted to produce deceptive thermal signatures on an inflatable decoy is U.S. Statutory Invention Registration (SIR) H308 to Tutin et al. The Tutin et al SIR teaches, as part of the use of a fabric-covered frame aircraft decoy, mixing metal particles with the fabric paint to increase the infrared and radar signatures of the decoy over its entire surface.
The prior art also includes using pyrotechnics to produce a deceptive thermal signature.
Unfortunately, all of the prior art, both that now used and that which may be adapted in the future, are add-on solutions, increasing complexity and cost. None of the prior art teachings take advantage of some inherent feature of inflatable decoys to provide deceptive thermal signatures. Such a solution would be simpler, more convenient and less expensive.
Thus it is seen that there is a need for an inflatable decoy that provides a deceptive thermal signature without the need for expensive and complicated add-on apparatus.
It is, therefore, a principal object of the present invention to provide an inflatable decoy target that utilizes its inherent supply of pressurized air to help produce thermal contrast detailing over the surface of the decoy.
It is another object of the present invention to provide different methods for heating the pressurized air used to enhance the thermal contrast.
It is a further object of the present invention to provide a general method for making thermal radiance area sources and patterns.
It is a feature of the present invention that only a single heat source, or heater, is needed for each decoy.
It is a further feature of the present invention that the heater is separate from the decoy and can thus provide heat to more than one decoy at the same time.
It is an advantage of the present invention that the separate heater is not destroyed with the decoy.
It is a further advantage of the present invention that the heater can be integrated with the inflation blower, and the same inflation blower can be used with both heated and nonheated inflatable decoys.
It is another advantage of the present invention that its fabrication will be a straightforward and inexpensive modification to already existing inflatable decoy construction methods.
These and other objects, features and advantages of the Present invention will become apparent as the description of certain representative embodiments proceeds.